Various types of enzymes have long been used in laundry detergents to assist in the removal of certain stains from fabrics. Each class of enzyme (amylase, protease, etc.) generally catalyzes a different chemical reaction. For example, protease enzymes are known for their ability to hydrolyze (break down a compound into two or more simpler compounds) other proteins. This ability has been taken advantage of through the incorporation of naturally occurring or engineered protease enzymes to laundry detergent compositions.
In recent years the use of enzymes has also been investigated for use in automatic dishwashing compositions. Unfortunately, many enzymes, such as many conventional protease enzymes, do not translate well into the wash environment. Specifically, thermal stability, pH stability, oxidative stability and substrate specificity need to be optimized to ensure satisfactory performance.
U.S. Pat. No. RE 34,606 to Estell et al. discloses the modification of subtilisin amion acid residues corresponding to positions in Bacillus amyloliquefaciens subtilisin tyrosine −1, aspartate +32, asparagine +155, tyrosine +104, methionine +222, glycine +166, histidine +64, glycine +169, phenylalanine +189, serine +33, serine +221, tyrosine +217, glutamate +156 and alanine +152.
U.S. Pat. No. 5,182,204 discloses the modification of the amino acid +224 residue in Bacillus amyloliquefaciens subtilisin and equivalent positions in other subtilisins which may be modified by way of substitution, insertion or deletion and which may be combined with modifications to the residues identified in U.S. Pat. No. RE 34,606 to form useful subtilisin mutants or variants. U.S. Pat. No. 5,182,204 further discloses the modification of many amino acid residues within subtilisin, including specifically +99, +101, +103, +107, +126, +128, +135, +197 and +204.
U.S. Pat. No. 5,155,033 discloses similar mutant subtilisins having a modification at an equivalent position to +225 of B. amyloliquefaciens subtilisin.
U.S. Pat. Nos. 5,185,258 and 5,204,015 disclose mutant subtilisins having a modification at positions +123 and/or +274.
U.S. Pat. No. 4,914,031 discloses certain subtilisin analogs, including a subtilisin modified at position +76.
U.S. Pat. No. 5,679,630 to Baeck et al. discloses cleaning compositions comprising a protease variant including substitutions of amino acid residues with other amino acid residues at positions corresponding to position 76 in combination with one or more of the following positions 99, 101, 103, 104, 107, 123, 127, 105, 109, 126, 128, 135, 156, 166, 195, 197, 204, 206, 210, 216, 217, 218, 222, 260, 265 and/or 274 of Bacillus amyloliquefaciens subtilisin, and one or more cleaning composition materials.
However, there continues to exist a need for proteases, particularly serine proteases, that provide improved and enhanced cleaning ability when used in detergent and cleaning compositions.
Further, the specific combinations claimed in the present application are not identified in any of these prior art references.